The role of an ISP (Internet Service Provider, internet service provider) is mainly to provide internet access, and is required to solve the problem of traffic engineering (TE, Traffic Engineering), that is, to specify an optimal path for the traffic to minimize network congestion. The role of a CP (Content Provider, content provider) is to provide required content for a user, and is required to solve the problem of server selection (SS, Server Selection), that is, to specify an optimal server for a different user to minimize end-to-end delay. When the ISP and the CP accomplish the TE and the SS, respectively, it is not a global optimal state from the perspective of the entire network.
To obtain optimal performance of the entire network, currently people begin attempting joint optimization (Joint Optimization) of the TE and the SS, and use a Nash bargain solution (NBS, Nash Bargain Solution) and a convex optimization technique in a game theory to implement a cooperative game on the given TE and SS that are two optimization problems, so as to achieve global optimal balance.
A TE and SS joint optimization mathematical model established by using the NBS is a constrained convex optimization problem. In the prior art, a method for solving the joint optimization based on a centralized manner exists. It is assumed in the scheme that a certain computing device gathers entire network state information required for solving the optimization problem, adopts the centralized manner to obtain an optimal solution to a system, and applies the optimal solution in the network, to perform a route change policy and a new server selection policy. However, the scheme has bad extensibility. With the expansion of the network scale, time consumed for gathering information and computing increases rapidly. If the joint optimization is applied in a network of a larger scale, for example, an entire metropolitan area network or even a nation wide backbone network, real-time application of the existing method for joint optimization in the network is difficult to be guaranteed.